The code doesn't compile as presented because of the redefinition of `file`. If
you change the second invocation of `openAsync` to `file = openAsync(filename,
fmRead)` the code will compile. The index error you get from running the code
is another matter though. I think its a potential bug in the Nim standard
library, but someone who knows more than me should verify that. Here's what I
do know:
This is the implementation of readLine:
proc readLine*(f: AsyncFile): Future[string] {.async.} =
## Reads a single line from the specified file asynchronously.
result = ""
while true:
var c = await read(f, 1)
if c[0] == '\c':
c = await read(f, 1)
break
if c[0] == '\L' or c == "":
break
else:
result.add(c)
Run
The index error comes from accessing the first element of `c` when `c` is the
empty string. The documentation from `read` says: "If the file pointer is past
the end of the file then an empty string is returned." So I feel that the fact
that `readLine` errors on `read` returning the empty string, means that this is
a bug. I added an extra check to make sure `c` isn't empty in my local version
of Nim, and the program now runs correctly.
Again, I'm not a Nim dev, so I'm not really sure if this is a bug or not.
